Unlike a piston engine, where the cylinder is cooled by the incoming charge after being heated by combustion, the rotor housings of rotary combustion engines, such as Wankel engines, are constantly heated on one side and cooled on the other, leading to high local temperatures and unequal thermal expansion around the engine housing. Indeed, in a rotary internal combustion engine, the four different phases of the working cycle-intake, compression, combustion/expansion and exhaust, always occur in their own parts of the housing. The portion of the housing in which the intake and compression phases occur generally forms the “cold region” of the engine, whereas the portion of the housing in which the combustion and the exhaust phases occur generally forms the “hot region” of the engine. Relatively complex cooling schemes may be required to cool the hot regions.